Isodicentric (X)(q13): A new characteristic chromosomal anomaly in myeloproliferative syndrome?

An elderly woman had dysmyelopoietic syndrome with a rapidly fatal course. On initial marrow and unstimulated blood cell examination a structural anomaly of the X chromosome was observed with a 46,X,idic(X)(q13) karyotype with the exception of two cells showing a 47,XXX karyotype. Peripheral blood lymphocytes showed a normal 46,XX karyotype. The specificity of these findings is discussed.